Change top left page link wording and target on single blog posts

HI,
on our page single blog entries look like this:

http://www.praxis-christiane-moeller.de/allgemein/vitamin-b12-mangel-und-nervenschmerzen/

I want to change the wording “Blog – die aktuellsten Neuigkeiten” and also the related link target. This should not route as now towards the start/homepage, but towards the blog overview page : http://www.praxis-christiane-moeller.de/kontakt-service-info/aktuelles-service/

For the first aspect I´ve seen an older post, but this was not really clear for me..

thx a lot for your help acc. & best regards, Tilman